/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */

package org.apache.bifromq.basecrdt.core.internal;

import static org.apache.bifromq.basecrdt.core.internal.ProtoUtils.dot;
import static org.apache.bifromq.basecrdt.core.internal.ProtoUtils.replacements;
import static org.apache.bifromq.basecrdt.core.internal.ProtoUtils.singleValue;

import org.apache.bifromq.basecrdt.core.api.MVRegOperation;
import org.apache.bifromq.basecrdt.proto.Replacement;
import com.google.protobuf.ByteString;

class MVRegCoalesceOperation extends CoalesceOperation<IDotFunc, MVRegOperation> {
    MVRegOperation op;

    MVRegCoalesceOperation(ByteString replicaId, MVRegOperation op) {
        super(replicaId);
        coalesce(op);
    }

    @Override
    public void coalesce(MVRegOperation op) {
        this.op = op;
    }

    @Override
    public Iterable<Replacement> delta(IDotFunc current, IEventGenerator eventGenerator) {
        long ver = eventGenerator.nextEvent();
        switch (op.type) {
            case Write:
                return replacements(dot(replicaId, ver, singleValue(replicaId, ver, op.value)), current);
            case Reset:
            default:
                return replacements(dot(replicaId, ver), current);
        }
    }
}
